Source contributions to two super dust storms over Northern China in March 2021 and the impact of soil moisture.

Two extremely devastating super dust storms (SDS) hit Mongolia and Northern China in March 2021, causing
many deaths and substantial economic damage. Accurate forecasting of dust storms is of great importance for
avoiding or mitigating their effects. One of the most critical factors affecting dust emissions is soil moisture, but
its value in desert exhibits significant uncertainty. In this study, model experiments were conducted to simulate
dust emissions using four soil moisture datasets. The results were compared with observations to assess the ef-
fects of soil moisture on the dust emission strength. The Integrated Source Apportionment Method (ISAM) was
used to track the dust sources and quantify the contribution from each source region to the dust load over the
North China Plain (NCP), Korea peninsula, and western Japan. The results show large differences in the dust load
depending on the soil moisture datasets used. The high soil moisture in the NCEP dataset results in substantial
underestimation of the dust emission flux and PM10 concentration. Despite a minor overestimation of PM10
concentrations in many Northern China cities, the ERA5 dataset yields the best simulation performance. During
the two SDS events, about 7.5 Mt dust was released from the deserts in Mongolia and 2.8 Mt from the deserts in
China. Source apportionment indicates that the Mongolian Gobi Desert is the dominant source of PM10 in the
NCP, Korea peninsula, and western Japan, accounting for 60 %–80 %, while Inner Mongolia contributed 10 %–
20 %